Studies On Residual Determination And Degradation Of Prochloraz On Orange And In Soil

Prochloraz, as a broad spectrum fungicide which is has a obvious inhibitive effect to most of the ascomycetes separately and imperfect fungi. It could be used by mixed with many other fungicide, herbicide, insecticide, and also has a remarkable control efficiency to those type of fungi Hence, the research are of great meaning to the residual degradation and determination on orange and in soil.Nowadays the date of residues for prochloraz in the growing season of orange and soil have not yet been reported, the research of residues for prochloraz only concern the preservation of orange Therefore, in order to determine the pesticide residues of prochloraz in the growing season of orange and soil, this paper used field trials and trials of laboratory to evaluate the security of prochloraz in the growing season of orange and soil and establishing reasonable method of use of prochloraz in orange. In this paper, The main ideas and conclusion of the thesis is as follows:1.A method was developed for determination of prochloraz residue in oranges and soil by gas chromatographySamples were extracted with acetone, purified by liquid-liquid Patition and alumininia chromatographic column, and washed by petroleum ether. The elution was evaporated and the residue was dissolved in petroleum ether, and analyzed by GC-ECD.The method was easy and fast. The analytical conditions of gas chromatography:RTX-1701(30x0.25mm×0.25μm), column temperature:245℃, detector temperature:300℃, Carrier flow:2.5ml·min-1, use the qualitative method of retention time, detected by ECD, average reoveries of 2,4,6-trichlorophenol from fortified orange pulp, peel and soil at levels of 0.1mg/L-20mg/L were in the range from 89.95%-98.40%,91.17%-95.78% and 90.33%-101.35% respectively, relative standard deviation were in the range from 2.07%-5.31%,6.36%-6.87% and 3.79%-7.09%.2. The field experiment of residue dynamics and final residue of prochloraz in orange and soil.The Result of the residue dynamics experiment shows that prochloraz degraded rapidly in the orange pulp and peel, but slowly in the soil relatively.The half-life of prochloraz in the former was 4.61d to 10.60d and 3.19d to 4.77d, yet in the latter was 18.50d to 35.20d. The degraded speed of prochloraz in soil is relevant to geographic position. The degraded speed of prochloraz in the orange pulp ascended first and then descended. The degradation of prochloraz in soil, pulp and peel complied the first-order kinetic equationThe Results of final residue experiment shows that the residue of prochloraz in the orange and soil were small. The residue of prochloraz in the orange pulp and peel was lower than 0.05mg/kg about 21d after harvesting; the residue of prochloraz in the soil ranged from 0.02mg/kg to 0.55mg/kg about 21d after harvesting. The residue of prochloraz in the orange pulp and peel were all lower than 0.01mg/kg about 45d after harvesting; the residue of prochloraz in the soil were all lower than 0.1mg/kg about 45d after harvesting.